The present invention concerns a procedure and means for sterilizing or disinfecting instruments, in particular thermosensitive instruments in a vacuum chamber, advantageously in an autoclave, in which sterilization or disinfection is performed with a powerful oxidizing agent which is an organic peracid.
The use takes place particularly in institutions related to health such as hospitals, out-patient departments, etc., as well as in the pharmaceutical industry.
A plurality of methods are in use in hospitals, etc., for sterilizing thermosensitive objects, the most important of these being use of ethylene oxide, formaldehyde gas, glutaridialdehyde, .beta.-propiolactone, and irradiation sterilization.
However, procedures currently in use involve several practical problems and drawbacks.
Ethylene oxide is a very toxic substance. It is carcinogenic, penetrates deeply into most materials and adheres to them strongly. Therefore, objects to be sterilized are required to be ventilated for a long period of time, for one day and night and even up to several months. In order to render ethylene oxide safer, it is mixed with Freon gas, however this gas ends up in the atmosphere and thereby leads to disintegration of the ozone layer. Ethylene oxide is also used in pure form. However, in this state it is an easily flammable and explosive substance.
Recently, formaldehyde has also been frequently used. This substance is extremely toxic and causes allergies. Additionally, it has an odor which adheres to the goods being sterilized, and also remains therein. The ventilation time is about twenty-four hours.
Additionally, a commonly used glutaric aldehyde may be noted. It is used in liquid form and another sterilizing substance needs to be used to activate the same. The subsequent flushing and drying of objects endangers sterilization. Therefore, sterilization is no longer discussed in this context; the term antiseptic preparation is used instead.
One more substance that has been used is .beta.-propiolactone. Disadvantages related to this substance are, for instance, that it is extremely dangerous and has an extremely powerful carcinogenic effect.
Irradiation sterilization cannot be accomplished in small or minor units, since it requires comprehensive and expensive installations and extensive protective measures. Generally, irradiation sterilization per target is allowed to be carried out only once.
In European Patent No. 0,109,352, a procedure for sterilizing thermosensitive objects is presented using 4 to 7% peracetic acid as a sterilizing substance, in which objects to be sterilized are sterilized when packed in a chamber which is at 10 to 100 mbar pressure. A drawback also of this procedure is impracticality in certain respects, specifically concerning the relatively long sterilizing time, while the dilution of the treatment preparation in water is disadvantageous in the procedure of European Patent No. 0,109,352 for two reasons. Firstly, the moisture concentration (mg per liter) to be achieved is again reduced, which is decisive in view of the effect. Secondly, as a result of the higher temperature, hydrolytic transformation of the peracetic acid into acetic acid and hydrogen peroxide takes place.
No agent or method without these accompanying drawbacks has been tried before. It is therefore to be noted that no agent without any danger is available for rapid sterilizing or thermosensitive objects.